001/*
002 * (C) Copyright 2017 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     bdelbosc
018 */
019package org.nuxeo.runtime.pubsub;
020
021import java.time.Duration;
022import java.util.List;
023import java.util.Map;
024import java.util.Random;
025import java.util.function.BiConsumer;
026
027import org.apache.commons.lang3.StringUtils;
028import org.apache.commons.logging.Log;
029import org.apache.commons.logging.LogFactory;
030import org.nuxeo.lib.stream.computation.Record;
031import org.nuxeo.lib.stream.log.LogAppender;
032import org.nuxeo.lib.stream.log.LogRecord;
033import org.nuxeo.lib.stream.log.LogTailer;
034import org.nuxeo.runtime.api.Framework;
035import org.nuxeo.runtime.stream.StreamService;
036
037/**
038 * A Pub/Sub provider based on Nuxeo Stream.
039 *
040 * @since 10.1
041 */
042public class StreamPubSubProvider extends AbstractPubSubProvider {
043    private static final Log log = LogFactory.getLog(StreamPubSubProvider.class);
044
045    public static final String GROUP_PREFIX = "pub-sub-node-";
046
047    protected static final String NODE_ID_PROP = "repository.clustering.id";
048
049    protected static final String LOG_CONFIG_OPT = "logConfig";
050
051    protected static final String DEFAULT_LOG_CONFIG = "default";
052
053    protected static final String LOG_NAME_OPT = "logName";
054
055    protected static final Random RANDOM = new Random();
056
057    protected String logConfig;
058
059    protected String logName;
060
061    protected LogAppender<Record> appender;
062
063    protected Thread thread;
064
065    @Override
066    public void initialize(Map<String, String> options, Map<String, List<BiConsumer<String, byte[]>>> subscribers) {
067        log.debug("Initializing ");
068        super.initialize(options, subscribers);
069        logConfig = options.getOrDefault(LOG_CONFIG_OPT, DEFAULT_LOG_CONFIG);
070        logName = options.get(LOG_NAME_OPT);
071        if (StringUtils.isBlank(logName)) {
072            throw new IllegalArgumentException("Missing option logName in StreamPubSubProviderDescriptor");
073        }
074        appender = Framework.getService(StreamService.class).getLogManager(logConfig).getAppender(logName);
075        startConsumerThread();
076        log.debug("Initialized");
077    }
078
079    protected void startConsumerThread() {
080        Subscriber subscriber = new Subscriber();
081        thread = new Thread(subscriber, "Nuxeo-PubSub-Stream");
082        thread.setUncaughtExceptionHandler((t, e) -> log.error("Uncaught error on thread " + t.getName(), e));
083        thread.setPriority(Thread.NORM_PRIORITY);
084        thread.setDaemon(true);
085        thread.start();
086    }
087
088    @Override
089    public void publish(String topic, byte[] message) {
090        appender.append(topic, Record.of(topic, message));
091    }
092
093    @Override
094    public void close() {
095        appender = null;
096        if (thread != null) {
097            thread.interrupt();
098            thread = null;
099            log.debug("Closed");
100        }
101    }
102
103    public class Subscriber implements Runnable {
104
105        @Override
106        public void run() {
107            // using different group name enable fan out
108            String group = GROUP_PREFIX + getNodeId();
109            log.debug("Starting subscriber thread with group: " + group);
110            try (LogTailer<Record> tailer = Framework.getService(StreamService.class)
111                                                     .getLogManager(logConfig)
112                                                     .createTailer(group, logName)) {
113                // Only interested in new messages
114                tailer.toEnd();
115                for (;;) {
116                    try {
117                        LogRecord<Record> logRecord = tailer.read(Duration.ofSeconds(5));
118                        if (logRecord == null) {
119                            continue;
120                        }
121                        Record record = logRecord.message();
122                        localPublish(record.key, record.data);
123                    } catch (InterruptedException e) {
124                        Thread.currentThread().interrupt();
125                        log.debug("Subscriber thread interrupted, exiting");
126                        return;
127                    }
128                }
129            }
130
131        }
132    }
133
134    protected String getNodeId() {
135        String nodeId = Framework.getProperty(NODE_ID_PROP);
136        if (StringUtils.isBlank(nodeId)) {
137            return String.valueOf(RANDOM.nextLong());
138        }
139        return nodeId.trim();
140    }
141}